1. Field of the Invention
The present invention relates to a motor control device and a magnetic pole position estimation precision confirming method, which can confirm magnetic pole position estimation precision.
2. Description of Related Art
Motor control devices need to supply a drive current in accordance with a motor's magnetic pole position at the time of driving a motor. The magnetic pole position is detected using a magnetic pole position sensor such as a hole device attached to the motor. If the motor is not provided with such a magnetic pole position sensor, the motor control device needs to estimate the magnetic pole position in any way.
For example, Japanese Unexamined Patent Application Publication No. 2003-088166 discloses a motor control device equipped with an initial magnetic pole position estimation unit, in which the initial magnetic pole position estimation unit estimates a magnetic pole position of a motor upon power-on to determine an initial magnetic pole position and subsequently derives an estimated magnetic pole position from a position signal of an encoder and an initial estimated magnetic pole position.
The initial magnetic pole position estimation unit includes a position reference waveform generating unit for generating a 2-period, S-shaped position reference pattern, a dq mode determination unit for determining whether a waveform pattern corresponds to a first period (q-axis control mode) or a second period (d-axis control mode), a position reference monotonic increase determination unit for identifying a portion that exhibits a monotonic increase in position reference pattern of the q-axis mode, a position reference monotonic increase determination unit for identifying a portion that exhibits a monotonic increase in position reference pattern of the d-axis mode, and an initial magnetic pole position correcting unit for adding data about a default initial magnetic pole position and data about an arbitrarily estimated initial magnetic pole position to obtain a final corrected initial magnetic pole position.
Further, the above motor control device issues any position reference and checks whether positional adjustment is completed within a predetermined period in order to confirm magnetic pole position precision after the completion of magnetic pole position estimation. In this way, the device confirms magnetic pole position precision.